The present invention relates to a device which holds plants or trees substantially vertical against wind and other forces of nature. More particularly, the present invention relates to a multifunctional device which supports the stem of a plant above ground level, protects the base of the stem from damage close to and at ground level, and efficiently applies fertilizer to the roots of the plant under ground level, which device is designed for maximizing access to the growing plants for both personnel and equipment.
It is common practice in commercial agriculture to grow young plants, such as tree plants, in one location at relatively high density and to transfer them later for cultivation in another location at a lower density. Depending on the type of plant involved, support of the main stem and/or branches may be required before transfer, after transfer, or both before and after transfer. For other plants no transfer is required but support of the young plants is necessary until the main stem or trunk becomes strong enough to resist wind and other natural forces.
The need for stabilizers or support devices for young plants being grown commercially is well recognized and many previous technologies have tried to address this need. The prior art can be divided into those devices which require multiple points of attachment to the ground (e.g., U.S. Pat. Nos. 332,729; 4,562,662; 4,649,666; 4,870,781; 5,129,179; and 5,402,600) and those devices which require only a single point of attachment to the ground (e.g., U.S. Pat. Nos. 349,435; 4,738,050; 4,881,342; 5,335,448; and 5,605,010).
Devices with multiple points of attachment to the ground are effective in preventing rotation of the supported plant with respect to the support device, however, they require more labor to install and make it more difficult for workers and equipment to move freely about the production area. Both additional labor and restriction of movement in the growing area therefore constitute an inherent disadvantage of such devices.
Prior art devices with single points of attachment to the ground allow the plant to rotate with respect to the support device, but are installed with less labor and allow more freedom of movement in the growing area after installation. Thus efficiency in preventing rotation of the plant has previously been sacrificed in order to reduce the labor associated with installation and permit greater freedom of movement in the growing area.
One device extant in the prior art combines the function of fertilizer application with the function of plant support (U.S. Pat. No. 4,870,781). This prior art device relies on multiple points of attachment to the ground, with the associated disadvantages described above. Furthermore, this device is ineffective with respect to fertilizer delivery because it relies on trios of stakes containing fertilizer which are installed at a great distance from the plant to be fertilized.
Since the fertilizer diffuses through the ground radially away from the stakes, roughly two thirds of the fertilizer from each stake moves away from the plant to be fertilized. The efficiency of delivery which may be achieved by placing a delivery device close to the base of a plant has been recognized in the prior art (U.S. Pat. No. 5,605,010), but only with respect to water, not fertilizer.
The prior art also includes devices for protecting the trunks of trees (U.S. Pat. Nos. D403,929; 5,819,468; 5,048,229; and D298,998), although not in conjunction with the support of said trees. These prior art devices are designed primarily for use with adult trees which are growing slowly.
There is thus a great need for, and it would be extremely advantageous to have, a plant support device with a single point of attachment to the ground, capable of supporting the plant in a non-rotatable fashion while simultaneously delivering fertilizer to the supported plant in an efficient manner and protecting the base of the plant from mechanical and chemical damage.